POMONA - Pomona Valley Hospital Medical Center has begun replacing equipment used to perform mammograms with new technology better at early detection of breast cancer.

The hospital started using the new mammography imaging equipment at its health centers in Chino Hills and Claremont two weeks ago.

It is making preparations to replace equipment at the hospital's Robert and Beverly Lewis Family Cancer Care Center.

In total four new 3-D breast imaging machines are expected to be in operation by mid-December, hospital spokeswoman Kathy Roche said.

On the surface tomosynthesis, as the technology is also known, is not much different from what is available at most medical imagining facilities.

However, the four machines, which cost about a total of $1.8million, are able to show tiny problems, such as calcifications and masses in a woman's breast, said Dr. Johnson Lightfoote, the hospital's medical director of radiology.

The machine is able to capture multiple images of a woman's breast.

"Tomosynthesis allows us to see through and look at separate sections of the breast that are 1 millimeter thick," Lightfoote said.

Radiologists are then able to review the images and pinpoint irregularities that may not have been as clear in the past.

With the new technology, patients are less likely to be called back for another test. But if something is detected they are also more likely to be called back for further tests, he said.

For patients the process is much the same with one difference: In many instances, there is less discomfort with the new technology.

Claremont resident Nancy Magnusson was the first patient to undergo 3-D mammography at the Claremont facility.

Magnusson, who was scheduled to have the annual test performed in August, said she volunteered to have it done on the new system this fall.

"It's much more comfortable. It didn't pinch. I didn't feel anything," said Magnusson who is a member of the Pomona Valley Hospital Medical Center Auxiliary, in addition to being a former member of the hospital's board of directors and an emeritus member of the hospital's foundation.

Magnusson said she's spoken with women about the new technology and encouraged them to take advantage of the hospital's low-cost breast screening services.

The hospital is the only one in the region to have switched all of its mammography machines to the new 3-D technology, Roche said.

The technology is one that most hospitals have begun to incorporate or are working to acquire, said John Morgan, a professor of cancer epidemiology at Loma Linda University in Loma Linda and a cancer epidemiologist with the California Cancer Registry, which is part of the state Department of Public Health.

The new 3-D mammography technology will bring about a slight increase in discovering cancer cases but in the long run it will result in a drop in the number of deaths resulting from the disease, he said.

Although the older equipment is very sensitive, the new technology is more so.

"It has higher sensitivity for detecting a malignancy," Morgan said.

He added, "we can see smaller masses and we can see them three dimensionalized."

Another benefit of the new technology is that it exposes women to lower levels of radiation, Morgan said.

Yet another advantage of the technology is that if a problem is detected less invasive testing and treatment can be used at earlier stages.